this is becoming common, some website are changing as to protect security,, they are not really taking into account smart tv users ,,where browsers can not be updated as things change. you will see this with big name companies, eg, Best Buy, Home depot, Costco etc,, all we can do is try to bring to their attention to their IT guys to fine tune the pages. I have had some success with informing some sites like Flipp.com , their response was amazing, this has happened twice with them, and within 3 days, they had tweaked what ever caused it,.so basically its all in their coding.The screen share you have is the same problem I had with Best Buy. but is viewable, but very slow . You might also find big name companies websites might work in other countries other than the one you are in. I guess we have to be patient and wait.But I do suspect in time it will only get worse.I might add some might find some sites open but with in seconds shut down. In the end, you are not alone.
by the way, I tried the website you are having trouble with and it works for me, and just to add my software version 05.50.55, but have found even updates don't cure these problems,

Just updated to firmware 05.50.55 and now can get BestBuy Canada, and homedepot, but not Costco Canada,, I also reset tv after update and no luck. I suspect some kind of security setting that is stopping webpage from opening. As a side note now after firmware up date, it was popping up it was updating remote... so after I reset I got the same message but this time in a short while it popped up remote was updated.. time will tell if the reset worked for remote message as I have read other who said the same thing about remoter message.

My lg smart tv,web browser Webos 3. has slowly over time lost a number of companies web sites no longer load,in my case ,Best Buy, Home Depot,Canadian Tire and now today Costco,these are Canadian Sites but U.S. sites do work. Anyone else with same problem?